1. Field of the invention
The present invention generally relates to a switching device for a power tool, and especially to a switching device with a simple rotary collar structure for adjusting the output axle of a power tool to be able to switch between a position for rotation and a position for rotation with impact.
2. Description of the Prior Art
A conventional power tool for driving a screwdriver or a drill can drive only by rotation. Sometimes, a body can not be drilled or a screw in the body can not be drawn out due to the sort of material it is made of or being overly fastened. Some manufacturers have developed output axles for power tools to be able to switch between a position for rotation and a position for rotation with impact in order to have the output axle simultaneously rotate and fast impact axially to hammer a drill into a body to be drilled or to screw out a screw having been overly fastened. In a Taiwan patent application No. 87,210,470, a rotary switching device having both rotation and impact functions is provided to make a power tool work in a more convenient and practical way. However, the rotary switching device includes more elements, the whole structure thereof is more complicated. This makes a higher cost of production.